The president and the attorney general have cited the Authorization for Use of Military Force, 115 Stat. 224, passed in the immediate aftermath of the attacks of 9/11, as providing additional authority for the NSA surveillance of Americans in contact with al Qaeda operating abroad. Carl Levin and Russ Feingold, falling over each other to display constitutional ignorance, say they cannot find anything in the AUMF to support such an assertion.

Like any legislation, this resolution is not perfect. I have some concern that readers may misinterpret the preamble language that the President has authority under the Constitution to take action to deter and prevent acts of international terrorism as a new grant of power; rather it is merely a statement that the President has existing constitutional powers. I am gratified that in the body of this resolution, it does not contain a broad grant of powers, but is appropriately limited to those entities involved in the attacks that occurred on September 11.

Much more important than Feingold’s admission against interest, though, is the SCOTUS opinion in Hamdi, which displays the sort of analysis of AUMF that appears to be part of the Administration’s reasoning on this point:

There is no bar to this Nation’s holding one of its own citizens as an enemy combatant. In Quirin, one of the detainees, Haupt, alleged that he was a naturalized United States citizen. 317 U. S., at 20. We held that “[c]itizens who associate themselves with the military arm of the enemy government, and with its aid, guidance and direction enter this country bent on hostile acts, are enemy belligerents within the meaning of … the law of war.” Id., at 37-38. While Haupt was tried for violations of the law of war, nothing in Quirin suggests that his citizenship would have precluded his mere detention for the duration of the relevant hostilities. See id., at 30-31. See also Lieber Code, ¶ ;153, Instructions for the Government of Armies of the United States in the Field, Gen. Order No. 100 (1863), reprinted in 2 Lieber, Miscellaneous Writings, p. 273 (contemplating, in code binding the Union Army during the Civil War, that “captured rebels” would be treated “as prisoners of war”). Nor can we see any reason for drawing such a line here. A citizen, no less than an alien, can be “part of or supporting forces hostile to the United States or coalition partners” and “engaged in an armed conflict against the United States,” Brief for Respondents 3; such a citizen, if released, would pose the same threat of returning to the front during the ongoing conflict.

In light of these principles, it is of no moment that the AUMF does not use specific language of detention. Because detention to prevent a combatant’s return to the battlefield is a fundamental incident of waging war, in permitting the use of “necessary and appropriate force,” Congress has clearly and unmistakably authorized detention in the narrow circumstances considered here.